Process for producing textured yarns

ABSTRACT

A process for producing textured yarns from synthetic fiber yarns including the steps of knitting the yarn, heating the knit yarn to stabilize it prior to dyeing, dyeing the yarn, unraveling the dyed yarn and texturing the dyed yarn. The resulting yarns exhibit combinations of bulk and uniformity which are superior to those previously available commercially.

United States Patent [72] Inventor William H. Kieffer Summit, NJ. [21}Appl. No. 802,640 22] Filed Feb. 26, 1969 [45] Patented May 25, 1971[73] Assignee Indian Head Inc.

New York, N.Y. Continuation-impart of application Ser. No. 758,677,Sept. 10, 1968, now abandoned.

[54] PROCESS FOR PRODUCING TEXTURED YARNS 10 Claims, 1 Drawing Fig. [52]U.S. Cl 28/72.1l, 28/72.16 [51] Int. Cl D02g 1/20 [50] Field ofSearch28/72.l1, 72.16; 8/ 1 54 [56] References Cited UNITED STATES PATENTS2,439,813 4/1948 Kulp et a1. 161/173 FILAMENT YARN PrimaryExaminerRobert R. Mackey AttarneyBrumbaugh, Graves, Donohue & RaymondABSTRACT: A process for producing textured yarns from synthetic fiberyams including the steps of knitting the yarn, heating the knit yarn tostabilize it prior to dyeing, dyeing the yarn, unraveling the dyed yarnand texturing the dyed yarn. The resulting yarns exhibit combinations ofbulk and uniformity which are superior to those previously availablecommercially.

KNIT

TEXTURING HEAT DYEING CONDITIONS DEK-NIT PATENTEUmwzsm 3579164 FILAMENTYARN I N VEN '1 0R WILLIAM H. KIEFFER Bysw fih l (CM A mvsrs 1 l PROCESSFOR PRODUCING TEXTURED YARNS knitting machine, and the tubing is heatedsufficiently to cause the yarn to be permanently set in the convolutionscaused by its knitted condition. The knit tubing is then deknit toprovide a yarn which has characteristic texture and bulk. Fabrics madefrom knit/deknit yarns have a characteristic handle and appearancewhich, while desirable for some uses, are unsuitable for manycommercially important types of fabrics.

Among other known procedures in the textile industry for producingtexture in filament yarns of synthetic polymers are the texturingoperation utilizing a stuffer box and the operation which applies afalse twist to the yarn. A stuffer box is described, for example, inChapter 7 of the publication Textured Yarn Technolog Vol. 1, I967, ofthe Monsanto Company. (Library of Congress Catalog Card No. 67-15639)The stuffer box imparts a characteristic crimp or texture to filamentyarns. Procedures which apply crimp or texture by false twisting arediscussed in Chapter 3 of the same publication.

The dyeing of filament yams is generally performed after the texturingoperation in order to improve dye uniformity over that which can beobtained on untextured yarns. Most textured yarns are dyed in the formof muffs or packages.

These conventional dyeing procedures generally result in loss of texturein the dyed yam to a greater or less degree depending on the type oftexture and the processing condition.

it has now been discovered that a level dyed textured filament yarn ofhighly desirable texture can be provided in an economical manner bycombining in sequence a knit/heat-set operation followed by dyeing,deknitting and a subsequent texturing step. The filament yarn isknitted, preferably as a tubing, and heat-set in the knitted condition.The tubing is then wound onto a dye package and dyed in accordance withconventional processes. After drying, the dyed tubing is deknitted andfed to a texturing'device, such as a stufier box, a false twist machine.or other texturing device. The result is a level dyed textured yarnwhich, when knitted or woven into a fabric for use in garments, homefurnishings, or industrial applications provides a fabric of improvedhand, texture and uniformity.

The process of the invention is further illustrated by the flow diagramof FIGURE 1 of the attached drawing.

Undyed yarns of the. same high quality are obtained by omitting thedyestuff or colorant from the dye bath during the dyeing step. All otherconditions, including the presence of moisture and the pressure andtemperature conditions used, remain the same. The resulting undyedyarns, when knitted into finished goods, give an outstanding hi-bulk andan excellent finish and hand to the fabric.

The first step of the process of this invention, that of knitting andheat-setting to form a crinkle-type yarn, is similar to the processknown to the prior art with the important exception that theheat-setting is accomplished at a temperature below that required forpennanent crimping of yarn from the particular polymer from which thefilament is made. On the other hand, the heat-set temperature must behigher than the dyeing temperature used for the particular yam beingtreated so that the heat-set knit yarn will be stabilizedagainstshrinking during the dyeing process. For example, the temperatureused for dyeing polyester yarns is in the order of 200270 F. theheat-set temperature to be used with such yarn must be in excess of suchdyeing temperature, and a temperature of about 300 F. has been found tobe suitable. As another example, nylon filament yams are usually dyed ata temperature in the range of 2l2 F. [have observed that excellentdyeing results may be obtainedwhen suchnylon yarn in knitted form hasbeen heat-set before dyeing at a temperature of about 225 F.

On the other hand, the heat-set temperature for the knitted yarn shouldbe lower than the temperature which will be used in the final texturingstep in order to secure optimum improvement in bulk, stretch and textureof the finished dyed yarn.

After heat-setting, as described, the knitted yarn may be dyed in aconventional manner. it has been observed that the heat-set knittedtubing forms compact dye packages which are substantially free fromshrinkage during dyeing and thatlevel dyeing is readily accomplished.

The deknitting step of the present invention involves merely theunraveling of the dyed yam tubing. The unraveled yarn is then fed to atexturing device such as a stuffer crimper or a false twist machine,either directly or after being subjected to any desired repackaging ortwisting or plying operation or operations as intermediate steps. Theyarn or tubing can be further treated after dyeing provided that suchtreatments are carried out at temperatures suitably below those of thefinal texturing step. The texturing step is carried out in aconventional manner and at a temperature which imparts the desiredpennanent texturing to the dyed yarn. The temperature at which thesedevices are operated is sufficiently high to substantially remove thecrimp imparted to the yarn during the heat-setting of the knitted yarntubing and to produce the permanent texturing crimp in the yarn. V

The following examples further illustrate the process of the presentinvention:

EXAMPLE I ISO-denier polyester filament yarn is knitted on a continuouscircular knitting machine having a 224-needle head. As the knittedtubing leaves the machine, it is heat-set at 300 F 1 The yarn tubing isthen wound on a suitable core into a dye package and dyed followingstandard procedures at 265 F.

After drying, the dyed tubing is deknitted and fed to a stuffer crimper,which is operated at a temperature of 325 F. This temperature issufficiently high to substantially remove the crimp imparted by thefirst heat-setting step described above before the permanent crimpimparted by the stuffer crimper becomes effective.

The resulting yarn .is dyed level and when knitted into finished goods,gives outstandingly high bulk and an excellent finish and hand to thefabric.

EXAMPLE ll Example I was repeated, except that the dyestuff was omittedfrom the'dye bath used in the dyeing step. All other conditions remainedthe same. The resulting yarn, when knitted into knitted cellent finishand hand to the finished goods.

EXAMPLE lll 70-denier nylon filament yarn is knitted on a continuouscircular knitting machine having a 340-needle head. As the knittedtubing leaves the machine it is heat-set at 225 F. The yarn tubing isthen wound into a dye package and dyed following standard procedures at2 10 F. After drying, the dyed tubing is deknitted and fed to a stuffercrimper, which is operated at a temperature of 380 F.

goods, gave outstanding hi-bulk and an ex- 3 EXAMPLE 1v EXAMPLE Vl-denier polyester filament yarn is knitted on a continuous circularknitting machine having a 224-needle head. As the knitted tubing leavesthe machine, it is heat-set at 300 F. The yarn tubing is then wound on asuitable core into a dye' package and dyed following standard proceduresat 265 F.

After drying, the dyed tubing is deknitted and fed to a stuffer crimper,which is operated at a temperature of 325 F. This temperatureissufficiently high to substantially remove the crimp imparted by thefirst heat-setting step described above before the permanent crimpimparted by the stuffer crimper becomes effective.

The resulting yarn is dyed level and when knitted into finished goodsgives outstandingly high bulk and an excellent finish and hand to thefabric.

EXAMPLE Vl ISO-denier polyester filament yarn is knitted on a continuouscircular knitting machine having a 224-needle head. As the knittedtubing leaves the machine, it is heat-set at 300 F. The yarn tubing isthen wound on a suitable core into a dye package and dyed followingstandard procedures at 265 F.

After drying, the dyed tubing is deknitted and fed through a false twisttexturing machine with 58 turns per inch at 410 F. and a spindle speedof 200,000 r.p.m.

After false twisting the dyed filament yarns may be autoclaved bystandard procedures and be used as a set textured" yarn or used withoutautoclaving as a stretch textured yarn.

EXAMPLE Vll 70-denier nylon filament yarn is knitted on a continuouscircular knitting machine having a 340-needle head. As the knittedtubing leaves the machine, it is heat-set at 225 F. The yam tubing isthen wound on a suitable core into a dye package and dyed followingstandard procedures at 210 F.

After drying the'dyed tubing is deknitted and fed through a false twisttexturing machine at a spindle speed of 225,000 r.p.m. with 76 turns perinch at a temperature'of 437 F. This temperature is sufficiently high tosubstantially remove the crimp imparted by the first heat-setting stepdescribed before the permanent crimp imparted by the false twist machinebecomes effective.

After false twisting, the dyed textured filament yarns may be autoclavedby standard procedures and be used as a set textured yarn or usedwithout autoclaving as a stretch textured yarn.

It will be appreciated that various modifications and changes can bemade in the herein disclosed process and product by those skilled in theart without departing from the essence of the invention and thataccordingly the invention is to be limited only within the scope of theappended claims.

.- 4 mam; n l. A method of making a dyedtexturedfilament yam of aheat-settable synthetic polymer comprising the steps of knittingfilament yarn from a synthetic polymer in a circular manner to form aknit tubing,

passing the knit tubing through a heating step to set the yarn at atemperature intermediate between normal dyeing temperatures and normaltexturing temperatures for the yarn, 1

forming a dye package of the knit tubing and dyeing the deknitting thedyed tubing,

texturing the yarn by a method which includes heat treatment at atemperature above that used to set the knit yarn before dyeing. I t 2.The method of claim 1, wherein the heat-settable synthetic polymer yarnis selected from the group consisting of polyamides, polyesters,polyolefins, cellulose acetates, biconstituent fibers, copolymers andgraft polymers.

3. The method of claim 1, wherein the texturing step is accomplished byusing a stufier crimper.

4. The method of claim 1, wherein the texturing step is accomplished byusing a false twist machine.

5. A method of making a dyed textured filament yarn of a heat-settablesynthetic polymer comprising the steps of knitting a filament yarn froma synthetic polymer in a circular manner to form a knit tubing,

heat-setting the knit tubing at a temperature intermediate betweennormal dyeing temperatures and normal texturing temperatures for theyarn,

uniformly dyeing the knit yarn at a dyeing temperature below the saidheat-setting temperature,

deknitting the dyed yarn, and

texturizing the yarn by a method'including heat treatment at atemperature higher than the said heat-setting temperature butinsufficient to damage the yarn.

6. The method of claim 5, wherein the heat-settable synthetic yarn isselected from the group consisting of polyamides, polyesters,polyolefins, cellulose acetates, biconstituent fibers, copolymers andgraft polymers.

7. The method of claim 6, wherein the texturing step is accomplishedusing a stuffer crimper.

8. A method of making a textured filament yarn of a synthetic polymercomprising the steps of knitting a synthetic polymer filament yarn in acircular manner to form a knit tubing, passing the knit tubing through aheating step at a temperature intermediate between normal dyeingtemperatures and normal texturing temperatures for the yarn to set theyarn, fonning a dye package of the knit tubing and subjecting thepackage to conditions of temperature, pressure and moisture normallyused in dyeing the yarn, deknitting the tubing, and texturing the yarnby a method which includes heat treatment at a temperature above thatused to set the knit yarn before fluid treatment in package form.

9. The method of claim 8, wherein the texturing step is accomplished byusing a stufi'er crimper.

10. The method of claim 8, wherein the synthetic polymer yarn isselected from the group consisting of polyamides, polyesters,polyolefins, cellulose acetates, biconstituent fibers, copolymers' andgraft polymers.

2. The method of claim 1, wherein the heat-settable synthetic polymeryarn is selected from the group consisting of polyamides, polyesters,polyolefins, cellulose acetates, biconstituent fibers, copolymers andgraft polymers.
 3. The method of claim 1, wherein the texturing step isaccomplished by using a stuffer crimper.
 4. The method of claim 1,wherein the texturing step is accomplished by using a false twistmachine.
 5. A method of making a dyed textured filament yarn of aheat-settable synthetic polymer comprising the steps of knitting afilament yarn from a synthetic polymer in a circular manner to form aknit tubing, heat-setting the knit tubing at a temperature intermediatebetween normal dyeing temperatures and normal texturing temperatures forthe yarn, uniformly dyeing the knit yarn at a dyeing temperature belowthe said heat-setting temperature, deknitting the dyed yarn, andtexturizing the yarn by a method including heat treatment at atemperature higher than the said heat-setting temperature butinsufficient to damage the yarn.
 6. The method of claim 5, wherein theheat-settable synthetic yarn is selected from the group consisting ofpolyamides, polyesters, polyolefins, cellulose acetates, biconstituentfibers, copolymers and graft polymers.
 7. The method of claim 6, whereinthe texturing step is accomplished using a stuffer crimper.
 8. A methodof making a textured filament yarn of a synthetic polymer comprising thesteps of knitting a synthetic polymer filament yarn in a circular mannerto form a knit tubing, passing the knit tubing through a heating step ata temperature intermediate between normal dyeing temperatures and normaltexturing temperatures for the yarn to set the yarn, forming a dyepackage of the knit tubing and subjecting the package to conditions oftemperature, pressure and moisture normally used in dyeing the yarn,deknitting the tubing, and texturing the yarn by a method which includesheat treatment at a temperature above that used to set the knit yarnbefore fluid treatment in package form.
 9. The method of claim 8,wherein the texturing step is accomplished by using a stuffer crimper.10. The method of claim 8, wherein the synthetic polymer yarn isselected from the group consisting of polyamides, polyesters,polyolefins, cellulose acetates, biconstituent fibers, copolymers andgraft polymers.